Fiat 9.55535-S1

The FIAT 9.55535‑S1 specification defines the requirements for engine oils for gasoline engines of passenger and crossover models Fiat, Alfa Romeo, Lancia and their turbocharged variants. Oils that meet this approval must have a viscosity in the 5W‑30/5W‑40 range, a high viscosity index, oxidation stability and effective wear protection, as well as a sufficient level of detergents and dispersants to prevent deposits on the catalyst. The specification calls for a low SAPS content, ensuring compatibility with three‑way catalysts and, when needed, with diesel particulate filter (DPF) systems in diesel variants. It covers both conventional and turbo‑diesel engines with direct injection, providing long‑term oil film stability under high temperatures and loads. Although FIAT 9.55535‑S1 remains current, newer approvals such as FIAT 9.55535‑GSX expand the requirements for better fuel‑economy performance and an even lower SAPS level, while remaining compatible with older engines.